Laminate and method for producing laminate

ABSTRACT

A laminate including a glass plate and a coating layer, wherein the coating layer includes one or more components selected from the group consisting of silicon nitride, titanium oxide, alumina, niobium oxide, zirconia, indium tin oxide, silicon oxide, magnesium fluoride, and calcium fluoride, wherein a ratio (dc/dg) of a thickness dc of the coating layer to a thickness dg of the glass plate is in a range of 0.05×10−3 to 1.2×10−3, and wherein a radius of curvature r1 of the laminate with negating of self-weight deflection is 10 m to 150 m.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a Continuation of U.S. patent applicationSer. No. 16/880,286, filed on May 21, 2020, which is a BypassContinuation Application of International Patent Application No.PCT/JP2019/032173 filed on Aug. 16, 2019, which claims priority ofJapanese Patent Application No. 2018-240262 filed on Dec. 21, 2018. Theentire contents of the foregoing applications are incorporated herein byreference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a laminate and a method for producingthe laminate, and more specifically to a support glass substrate usedfor supporting a processed substrate in a production step of asemiconductor package.

2. Description of the Related Art

In wafer level packages (WLP), a fan-out WLP has been proposed. With thefan-out WLP, it is known that a glass substrate that supports aprocessed substrate is used to reduce a dimensional change of theprocessed substrate. (For example, see Japanese Laid-Open PatentPublication No. 2017-30997)

However, as illustrated in FIG. 1 , the steps for producing WLP includesteps of high temperature conditions such as a step of laminating arelease layer and a step of generating a resin mold, and the substratemay be warped by heat.

To control warpage, an approach using a support glass substrate with asmaller warpage has been studied, but studies have not been conductedfor the purpose of cancelling warpage caused in a step of producing aWLP by warping or curving in advance the support glass substrate in adirection opposite to the warpage caused in the step of producing theWLP.

It is known that a warpage occurs when a glass substrate is coated witha thin film (International Publication No. 2017/204167), but techniquesfor efficiently enabling such a warpage or curvature with a thinner filmon a glass plate have not been studied.

SUMMARY OF THE INVENTION

It is easy to increase curvature of a laminate by increasing thethickness of a coating layer, but in a production step of a fan-out WLP,separation between a processed substrate and a support substrate isenabled by emitting visible light wavelength laser to a release layer,and therefore, the material of the coating layer and the thickness ofthe coating layer impede laser transmission, which result in problems.

Under such circumstances, a support glass substrate material having alarge curvature while maintaining visible light transmittance isdesired.

The inventors of the present application have found that the aboveproblems can be solved by a laminate having a particular curvature andconfiguration and a method for producing a laminate under a particularcondition.

More specifically, the present invention provides a laminate including aglass plate and a coating layer, wherein the coating layer includes oneor more components selected from the group consisting of siliconnitride, titanium oxide, alumina, niobium oxide, zirconia, indium tinoxide, silicon oxide, magnesium fluoride, and calcium fluoride, whereina ratio (dc/dg) of a thickness dc of the coating layer to a thickness dgof the glass plate is in a range of 0.05×10⁻³ to 1.2×10⁻³, and wherein aradius of curvature r1 of the laminate with negating of self-weightdeflection is 10 m to 150 m.

According to the present invention, a laminate with a large curvaturecan be provided while maintaining visible light transmission property.Furthermore, when the laminate is used as a support glass substrate, aWLP with a high degree of accuracy in dimension can be produced.

The object and advantages of the invention will be realized and attainedby means of the elements and combinations particularly pointed out inthe appended claims. It is to be understood that both the foregoinggeneral description and the following detailed description are exemplaryand explanatory and are not restrictive of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and further features of an embodiment will become apparentfrom the following detailed description when read in conjunction withthe accompanying drawings, in which:

FIG. 1 is an example of conventional WLP production steps (up to supportsubstrate release); and

FIG. 2 is an example of WLP production steps (up to support substraterelease) using a laminate according to the present invention as asupport glass substrate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an embodiment of the present invention will be explainedwith reference to the drawings.

A laminate and a method for producing the laminate according to thepresent invention will be explained. A numerical range between any givennumber “to” another number is to be understood as inclusive, i.e., thenumerical range includes these numbers before and after the term “to” asan upper limit value and a lower limit value, respectively, unlessotherwise specified.

[Glass Composition]

A composition of a glass plate used for a laminate according to thepresent invention is not particularly limited, and a known compositionwith a high visible light transmittance can be used. More specifically,a composition having a minimum transmittance (T %) of 60% or more at awavelength of 400 nm to 1000 nm can be used.

Compositions of the glass plate preferably include, as expressed inoxide-based mass percentage:

-   -   SiO₂ at 40% to 70%,    -   B₂O₃ at 0% to 15%,    -   MgO at 0% to 10%,    -   CaO at 0% to 10%,    -   SrO at 0% to 13%,    -   BaO at 0% to 40%,    -   Na₂O at 0% to 30%,    -   K₂O at 0% to 13%, and    -   Al₂O₃ at 0.5% to 15%.

More preferably, the compositions of the glass plate include, asexpressed in oxide-based mass percentage:

-   -   SiO₂ at 49% to 70%,    -   B₂O₃ at 4% to 13%,    -   MgO at 0% to 0.5%,    -   CaO at 0% to 8%,    -   SrO at 0% to 8%,    -   BaO at 0% to 13%,    -   Na₂O at 4% to 15%,    -   K₂O at 0.1% to 13%, and    -   Al₂O₃ at 4% to 13%.

When the composition is within this range, the visible lighttransmittance is excellent. In addition, in glass compositions of whichthe coefficients of thermal expansion are high, warpage is greatlyaffected by thermal treatment, and accordingly, the effect of thepresent invention is particularly significant.

[Glass Plate]

A glass plate is used for a laminate according to the present invention.For example, the glass plate is produced by forming the above glasscompositions into a plate having a predetermined shape (for example, aquadrangular shape or a disk shape).

A method for forming a glass plate is not limited, and for example,known methods such as a float method, a fusion method, and a roll-outmethod can be used. In the present invention, in order to greatly curvethe laminate, it is preferable that a glass plate has a certaincurvature before the glass plate is coated.

As a curvature of a glass plate before coating, a radius of curvature r0is preferably 200 m to 500 m, and more preferably 300 m to 400 m, withnegating of self-weight deflection. (These values are of real glassplate curvature, i.e., curvature inherent to only the glass plate,corrected to negate effects of deflection in relation to weight of theglass plate.) When the curvature of the glass plate before coating fallswithin this range, the curvature of a laminate caused by coatingexplained below increases.

For example, a glass plate that falls within such a condition can beeasily obtained by cutting out a portion having a curvature in the aboverange from a base plate produced by floating method.

A plate thickness (dg) of a glass plate is preferably 0.3 mm to 3.0 mm,more preferably 0.5 mm to 2.0 mm, and still more preferably 0.7 mm to1.2 mm. When the plate thickness (dg) of the glass plate falls withinthis range, the strength as the laminate appreciably increases, and theweight also falls within an acceptable range. Also, a chemicallystrengthened glass plate may be used.

[Coating Layer]

In the present invention, a coating layer is formed by coating the glassplate with a thin film. The coating layer includes one or morecomponents selected from the group consisting of silicon nitride,titanium oxide, alumina, niobium oxide, zirconia, indium tin oxide,silicon oxide, magnesium fluoride, and calcium fluoride. Silicon nitrideand titanium oxide are superior in visible light transmission propertyand superior in the effect of curving a laminate, and are thereforepreferable.

As a coating method, a known method such as a sputtering method, an ionassist deposition method, and an aerosol deposition method can be used.Among them, the sputtering method is preferable because it is excellentin the effect of curving a laminate. Then, a convex surface side of theglass plate having the curvature specified above is coated, therebyincreasing the curvature of the glass plate.

The thickness of the coating layer (dc) is preferably 0.05 μm to 1.2 μm,more preferably 0.1 μm to 1.0 μm, and still more preferably 0.4 μm to0.6 μm. When the thickness of the coating layer (dc) falls within thisrange, both of a large curvature of the laminate and a high visiblelight transmission property can be achieved.

[Laminate]

The laminate according to the present invention includes the glass plateand the coating layer. A radius of curvature r1 with negating ofself-weight deflection is in a range of 10 m to 150 m, and is preferablyin a range of 30 m to 100 m. When the radius of curvature r1 fallswithin this range, a WLP with a high degree of accuracy in dimension canbe produced.

A ratio (dc/dg) of a thickness (dc) of the coating layer to a thickness(dg) of the glass plate is 0.05×10⁻³ to 1.2×10⁻³, and preferably in arange of 0.4×10⁻³ to 0.5×10⁻³. When the ratio (dc/dg) falls within thisrange, both of a large curvature of the laminate and a high visiblelight transmission property can be achieved.

The thickness of the laminate is preferably 0.3 mm to 3.5 mm, morepreferably 0.5 mm to 2.5 mm, and still more particularly 0.7 mm to 1.3mm. When the thickness of the laminate falls within this range, both ofa high strength of the laminate and a high visible light transmissionproperty can be achieved.

The shape of the laminate is a quadrangular shape or a disk shape.

The laminate can be preferably used as a support glass substrate.

[Method for Producing Laminate]

The laminate according to the present invention can be produced bycoating the glass plate. A specific example of a preferable productionmethod has a condition including a step of, as illustrated in FIG. 2 ,coating a protruding side of the glass plate 11 having a curvature, ofwhich a radius of curvature r0 with negating of self-weight deflectionis 200 m to 500 m, with a thin film (coating layer) 12 including one ormore components selected from the group consisting of silicon nitride,titanium oxide, alumina, niobium oxide, zirconia, indium tin oxide,silicon oxide, magnesium fluoride, and calcium fluoride. By producingthe laminate under this condition, the laminate 10 of which the radiusof curvature r1 of the laminate 10 with negating of self-weightdeflection is 10 m to 150 m or less can be obtained in a preferablemanner.

EXAMPLES

Hereinafter, the present invention will be described in detail by way ofExamples and Comparative Examples. However, as long as advantages of thepresent invention can be achieved, embodiments can be changed asappropriate.

<Evaluation Sample Shape>

Glass plates in a disk shape having a diameter of 150 mm (6 inch) and aplate thickness of 1.0 mm coated under conditions as described in Table1 were used.

<Measurement Conditions and Evaluation Conditions>

[Measurement of Thickness of Glass Plate (Dg) and Thickness of CoatingLayer (Dc)]

Using a laser displacement meter (Dyvoce manufactured by Kohzu PrecisionCo., Ltd.) under a room temperature condition, the thickness dg of theglass plate before coating and the thickness dc of the laminate afterthe coating were measured. As a result, the thickness dg and thethickness dc were obtained.

[Radiuses of Curvatures (r0, r1) of Glass Plate and Laminate]

Using the laser displacement meter (Dyvoce manufactured by KohzuPrecision Co., Ltd.), the shapes of the samples were calculated throughshape simulation on the basis of the curvatures inherent to the samplesderived through self-weight deflection correction in “both sidesdifference calculation mode”. Then, the radiuses of curvatures werederived from the shapes obtained through the simulation.

A radius of curvature of a glass plate, before coating, with negating ofself-weight deflection is denoted as r0. A radius of curvature of aglass plate of a laminate, after coating, with negating of self-weightdeflection is denoted as r1.

[Evaluation of Curvature]

In general, the thicker a coating layer is, the larger a curvaturecaused by the coating becomes. For this reason, the curvature wasevaluated based on a value R expressed by Expression 1. Among ranges Ato D of the value R, ranges A, B, and C were evaluated as “acceptable”.R=r1(m)×dc(μm)  Expression 1<Ranges of R>

-   -   A: R≤30,    -   B: 30<R≤50,    -   C: 50<R<70,    -   D: 70≤R.        [Visible Light Transmission Property]

Using a spectrophotometer (V-700 manufactured by JASCO Corporation)under a room temperature condition, a minimum value (T %) of atransmittance of each sample at a wavelength of 400 to 1000 nm wasmeasured. Among ranges A to C of the minimum value (T %), ranges A and Bwere evaluated as “acceptable”.

<Ranges of T>

-   -   A: 80% T,    -   B: 60% T<80%,    -   C: T<60%

Example 1

A base plate (a length and width of 1000 mm and a thickness of 1.4 mm)of glass having a composition 1 (including, as expressed in masspercentage, SiO₂ at 56.9%, Al₂O₃ at 8.1%, CaO at 2.3%, SrO at 12.3%, andBaO at 20.4%) was obtained by floating method. A circular shape having aradius of 75 mm (a diameter of 150 mm) from a central portion of thebase plate was cut out from the base plate, so that a disk shaped glassplate was obtained. After, the disk shaped glass plate was chamfered,the disk shaped glass plate was polished by a double-sided lapping andpolishing machine (16B-N/F manufactured by HAMAI CO., LTD.), whereby theplate thickness (dg) was adjusted to 1.0 mm. The radius of curvature r0(caused by float method) of the glass plate was 370 m with negating ofself-weight deflection.

Thereafter, using a silicon target with a sputtering system(SIV-345XYSSS manufactured by ULVAC, Inc.), a silicon nitride film wasformed on a convexly curved surface of the glass plate by reactivesputtering so that a compressive stress of the film becomes 1 GPa. Thethickness (dc) of the coating layer was 0.5 μm. The evaluation resultsare shown in Table 1.

Example 2 to Example 7 and Comparative Examples 1 to 4

Operations were performed in a manner similar to the operation ofExample 1 except for changing the conditions to those as described inTable 1. The evaluation results are shown in Table 1.

TABLE 1 Glass dc dg dc/dg r0 r1 Evaluation Composition Coating LayerCoating Method (μm) (mm) (×10−3) (m) (m) T (%) R = r1 × dc Example 1Composition 1 Silicon Nitride Sputtering 0.5 1 0.5 370 55 84(A) 27.5(A) Example 2 Composition 2 Silicon Nitride Sputtering 0.5 1 0.5 370 5484(A) 27(A) Example 3 Composition 1 Titanium Oxide Sputtering 0.4 1 0.4370 60 75(B) 24(A) Example 4 Composition 1 Silicon Nitride Sputtering 11 1 370 37 60(B) 37(B) Example 5 Composition 1 Silicon NitrideSputtering 0.1 1 0.1 370 113 87(A) 11.3(A)  Example 6 Composition 1Silicon Nitride Ion Deposition 0.5 1 0.5 370 100 83(A) 50(B) Example 7Composition 1 Silicon Nitride Aerosol Deposition 0.7 1 0.7 370 98 80(A)68.6(C)  Comparative Example 1 Composition 1 Chromium Sputtering 0.5 10.5 370 70 <50(D)  35(B) Comparative Example 2 Composition 1 TantalumOxide Sputtering 0.8 1 0.8 370 640 84(A) 512(D)  Comparative Example 3Composition 1 Silicon Nitride Sputtering 1.5 1 1.5 370 11 55(D) 16.5(A) Comparative Example 4 Composition 1 Silicon Nitride Sputtering 0.5 1 0.51000 194 84(A) 97(D)(Mass Percentage)*Composition 1:

-   -   SiO₂: 56.9%,    -   Al₂O₃: 8.1%,    -   CaO: 2.3%,    -   SrO: 12.3%, and    -   BaO: 20.4%.        *Composition 2:    -   SiO₂: 68.9%,    -   Al₂O₃: 5.9%,    -   MgO: 4.1%,    -   CaO: 7.3%,    -   Na₂O: 14.6%, and    -   K₂O: 0.2%.

Although the preferred embodiment and examples of the present inventionhave been described in detail above, the present invention is notlimited to the embodiment and examples described above, and variousmodifications and substitutions can be applied to the embodiment andexamples described above without departing from the scope of the presentinvention.

What is claimed is:
 1. A laminate comprising a glass plate and a coatinglayer, a ratio (dc/dg) of a thickness dc of the coating layer to athickness dg of the glass plate is in a range of 0.05×10⁻³ to 1.2×10⁻³,a radius of curvature r1 of the laminate with negating of self-weightdeflection is 10 m to 150 m, and a minimum transmittance at a wavelengthof 400 nm to 1000 nm is 60% or more.
 2. The laminate according to claim1, wherein a composition of glass used for the glass plate includes, asexpressed in mass percentage: SiO₂ at 40% to 70%, B₂O₃ at 0% to 15%, MgOat 0% to 10%, CaO at 0% to 10%, SrO at 0% to 13%, BaO at 0% to 40%, Na₂Oat 0% to 30%, K₂O at 0% to 13%, and Al₂O₃ at 0.5% to 15%.
 3. Thelaminate according to claim 1, wherein the coating layer includes one ormore components selected from the group consisting of silicon nitride,titanium oxide, alumina, niobium oxide, zirconia, indium tin oxide,silicon oxide, magnesium fluoride, and calcium fluoride.
 4. The laminateaccording to claim 1, wherein a shape of the laminate is a quadrangularshape or a disk shape.
 5. The laminate according to claim 1, wherein thelaminate is used as a support glass substrate.
 6. A method for producingthe laminate according to claim 1, comprising: coating a protruding sideof a glass plate having a curvature, of which a radius of curvature r0with negating of self-weight deflection is 200 m to 500 m, with a thinfilm.
 7. The method for producing the laminate according to claim 6,wherein the coating method is a sputtering method.
 8. The laminateaccording to claim 1, wherein the ratio dc/dg is from 0.4×10⁻³ to1.2×10⁻³.
 9. The laminate according to claim 1, wherein the thickness dgis in a range of 0.3 mm to 3.0 mm, and the thickness dc is in a range of0.05 μm to 1.2 μm.
 10. The method for producing the laminate accordingto claim 6, wherein a composition of glass used for the glass plateincludes, as expressed in mass percentage: SiO₂ at 40% to 70%, B₂O₃ at0% to 15%, MgO at 0% to 10%, CaO at 0% to 10%, SrO at 0% to 13%, BaO at0% to 40%, Na₂O at 0% to 30%, K₂O at 0% to 13%, and Al₂O₃ at 0.5% to15%.
 11. The method for producing the laminate according to claim 6,wherein the coating layer includes one or more components selected fromthe group consisting of silicon nitride, titanium oxide, alumina,niobium oxide, zirconia, indium tin oxide, silicon oxide, magnesiumfluoride, and calcium fluoride.
 12. The method for producing thelaminate according to claim 6, wherein a shape of the laminate is aquadrangular shape or a disk shape.
 13. The method for producing thelaminate according to claim 6, wherein the laminate is used as a supportglass substrate.
 14. The method for producing the laminate according toclaim 6, wherein the ratio dc/dg is from 0.4×10⁻³ to 1.2×10⁻³.
 15. Themethod for producing the laminate according to claim 6, wherein thethickness dg is in a range of 0.3 mm to 3.0 mm, and the thickness dc isin a range of 0.05 μm to 1.2 μm.